This application has been submitted as a request for continuing support for a program of projects that has been designed to better understand the neurobiology and genetics of autism. The central organizing theme of the project is on studies of processes associated with language and social deficits in this syndrome. In its initial funding cycle the program included 3 funded projects designed to: a) provide a longitudinal study of the relations between language and theory of mind; b) develop a battery of computer based tasks that would differentiate nonverbal children with autism from children with severe autism, and c) explore the neurobiological underpinnings of language and communication abnormalities in autism with MRI. Three new projects are described in this continuation proposal. Project I proposes a detailed comparison of face processing in children with autism and controls. Project II proposes to examine the similarities and differences in language impairments in children with autism versus those with and without specific language development. Project III has been designed to provide a morphometric and functional MRI exploration of the neural substrates of social and language impairments in autism. These projects are to be carried out as a collaborative effort across Boston University Medical School; Tufts / New England Medical Center, and Harvard Medical School / Massachusetts General Hospital. These projects will be coordinated by a clinical and administrative core.